Field of the Invention
The present invention relates to an arrester and, more specifically, to an active lightning arrester for actively and quickly receiving lightning and safely discharging the charges of a thundercloud to the ground, thereby reducing the lightning frequency with respect to a protection object.
Background Art
In general, an arrester is provided to the uppermost end part of a building so as to safely discharge the charges accumulated in a thundercloud to the ground by forming a discharge path between the thundercloud and the ground.
In a fine day, the electric field of the ground is, in general, about 100V/m. However, if a thundercloud approaches, the electric field of the ground becomes about 10,000V/m and the potential difference between the thundercloud and the ground reaches one hundred million V.
However, if the charges filled in the thundercloud is equal to or less than a predetermined size or if a predetermined distance is maintained between the ground and the thundercloud, the air of the atmospheric layer serves as a good insulator such that no dielectric breakdown, that is, no lightning is generated between the ground and the thundercloud. However, the charges of a predetermined size or more filled in the thundercloud can break the insulation of the atmospheric layer whenever discharge conditions such as the distance, humidity and the like are satisfied between the ground and the thundercloud such that the charges of the thundercloud are discharged to the ground, thereby remaining the danger of lightning all the time.
Further, due to the recent tendency towards the high-rise and high-density buildings, a distance from a thundercloud and lightning to a building to be protected becomes decreased. Therefore, the present inventor has developed and suggested to protect a building by leading lightning into a stone needle part of an arrester as disclosed in U.S. Pat. No. 6,943,285, Korean Patent Laid-Open Publication No. 2004-0040512 and Korean Patent No. 0440616. However, when a building is protected by leading the lightning into the stone needle part of an arrester according to the prior art, the lightning can be leaded as intended in some cases. However, depending on natural conditions, an charging voltage between a building to be protected and a thundercloud and lightning becomes lower than an insulation breakdown voltage between the thundercloud and the stone needle part of the arrester of the building to be protected and thus the charges of the thundercloud can be discharged through any other conductors which are fixed and provided to the upper end portion of the building to be protected rather than the arrester. Therefore, the lightning is likely to hit the structures rather than to be leaded into the lightning arrester.
Further, the prior art has a further disadvantage that electric performance becomes deteriorated by the generation of rust since constituent elements except insulators are made from metal materials such as copper, steel and the like. In addition, in a region such as an industrial complex, a costal area and the like, where the concentration of salt, sulfurous acid and the like which can induce the corrosion of metal is relatively high, the corrosion rapidly progresses, thereby decreasing the mechanical strength and resulting in damage from external force such as strong wind, vibration and the like.
Furthermore, the prior art has still another disadvantage in conveying, installation and the like since the arrester mainly made from metal materials is a considerably heavy body which weighs several kilometers to scores of kilometers.